Elastic Stent Graft

• US 20140135897A1
• Filed: 01/31/2013
• Published: 05/15/2014
• Est. Priority Date: 11/13/2012
• Status: Active Grant

• Current Assignee: W. L. Gore & Associates (W.L. Gore & Associates)
• Original Assignee: W. L. Gore & Associates (W.L. Gore & Associates)
• Inventors: Cully, Edward H., Duncan, Jeffrey B., Kariniemi, Thomas E., Kariniemi, Ryan D., Kustusch, Jeffrey J., Nelson, Jared S.
• Granted Patent: US 9,931,193 B2
• Time in Patent Office: Days
• US Class Current: 623/1.13
• CPC Class Codes: A61F 2/07 Stent-grafts
• CPC Class Codes: A61F 2002/072 Encapsulated stents, e.g. wire or whole stent embedded in lining
• CPC Class Codes: A61L 31/048 obtained by reactions only involving carbon-to-carbon unsaturated bonds A61L31/041 takes precedence
• CPC Class Codes: C08L 27/18 Homopolymers or copolymers or tetrafluoroethene

Abstract

A stent graft including (1) a stent having a wall having at least one opening, an outer surface, and an inner surface and (2) a covering of a composite material having a least one expanded fluoropolymer membrane and an elastomer is provided. The cover can be used to cover the outer and/or the inner surface of the stent. The expanded fluoropolymer membrane contains serpentine fibrils. In exemplary embodiments, the fluoropolymer is polytetrafluoroethylene. The composite material may be axially and/or circumferentially wrapped around the stent. The composite material is fold-free throughout its operating diameter range and exhibits a sharp increase in stiffness at a predetermined diameter. The stent graft can be designed to have a stop point in either a radial or axial direction. The stent graft can advantageously be implanted undersized with respect to a nominal diameter without having material infolding.

Claims

1. A stent graft comprising:

a stent having a wall with at least one opening, an outer surface, and an inner surface; and

a cover affixed to said stent, said cover comprising a composite material comprising at least one expanded fluoropolymer membrane and an elastomer,

wherein said expanded fluoropolymer membrane comprises serpentine fibrils,

2. The stent graft of claim 1, wherein each said serpentine fibril has a width of about 1.0 micron or less.

3. The stent graft of claim 2, wherein each said serpentine fibril has a width of 0.5 micron or less.

4. The stent graft of claim 1, wherein said cover is wrinkle-free.

5. The stent graft of claim 1, wherein said cover is affixed to said outer surface.

6. The stent graft of claim 1, wherein said cover is affixed to said inner surface.

7. The stent graft of claim 1, wherein said cover is affixed to said outer surface and said inner surface.

8. The stent graft of claim 1, wherein said elastomer is present in pores of said fluoropolymer membrane.

9. The stent graft of claim 1, wherein said at least one expanded fluoropolymer membrane comprises a plurality of pores and said elastomer is present in substantially all of said pores.

10. The stent graft of claim 1, wherein the fluoropolymer membrane comprises polytetrafluoroethylene.

11. The stent graft of claim 1, wherein the fluoropolymer membrane comprises a microstructure of substantially only fibrils.

12. The stent graft of claim 1, wherein the fluoropolymer membrane comprises a plurality of serpentine fibrils.

13. The stent graft of claim 1, wherein the expanded fluoropolymer membrane comprises a microstructure of substantially only serpentine fibrils.

14. The stent graft of claim 1, wherein said composite material can be radially expanded up to a diameter beyond which further expansion is inhibited.

15. The stent graft of claim 1, wherein said cover is wrinkle free when radially expanded to about 90% of a nominal diameter.

16. The stent graft of claim 1, wherein said cover is wrinkle free when radially expanded to about 85% of a nominal diameter.

17. The stent graft of claim 1, wherein said cover is wrinkle-free when radially expanded to about 80% of a nominal diameter.

18. The stent graft of claim 1, wherein said composite material is free of wrinkles before loading and after deployment of said device.

19. The stent graft of claim 1, wherein said composite material is circumferentially wrapped around said stent.

20. The stent graft of claim 1, wherein said composite material is axially wrapped around said stent.

21. The stent graft of claim 1, wherein said composite material is helically wrapped around said stent.

22. The stent graft of claim 1, wherein said composite material is both circumferentially and axially wrapped around said stent.

23. The stent graft of claim 1, wherein the stent comprises a self-expanding stent.

24. The stent graft of claim 1, wherein elastic properties are present in the axial direction of the stent graft.

25. The stent graft of claim 1, wherein said elastomer is selected from the group consisting of perfluoromethylvinyl ether-tetrafluoroethylene copolymers, perfluoro(alkyl vinyl ether)-tetrafluoroethylene copolymers, silicones and polyurethanes.

26. An implantable graft comprising:

a tubular member comprising at least one expanded fluoropolymer membrane and an elastomer,

wherein said expanded fluoropolymer membrane comprises serpentine fibrils having a width of about 1.0 micron or less.

27. The implantable graft of claim 26, wherein each said serpentine fibril has a width of about 0.5 micron or less.

28. The implantable graft of claim 26, wherein said tubular member is wrinkle-free when radially expanded to about 80%.

29. The graft of claim 26, wherein said tubular member has elastic properties in the axial direction of said tubular member.

30. The graft of claim 26, wherein said tubular member has elastic properties in the radial direction of said tubular member.

31. The graft of claim 26, wherein said elastomer is present in pores of said fluoropolymer membrane.

32. The graft of claim 26, wherein said elastomer is from the group consisting of perfluoromethylvinyl ether-tetrafluoroethylene copolymers, perfluoro(alkyl vinyl ether)-tetrafluoroethylene copolymers, silicones and polyurethanes.

33. The graft of claim 26, wherein said fluoropolymer membrane comprises polytetrafluoroethylene.

34. The graft of claim 26, wherein said fluoropolymer membrane comprises a plurality of pores and said elastomer is present in substantially all of the pores of said fluoropolymer membrane.

35. The graft of claim 26, wherein the fluoropolymer membrane comprises a microstructure of substantially only fibrils.

36. The graft of claim 26, wherein the fluoropolymer membrane comprises a plurality of serpentine fibrils.

37. The graft of claim 26, wherein the expanded fluoropolymer membrane comprises a microstructure of substantially only serpentine fibrils.

38. The graft of claim 26, wherein said tubular member can be radially expanded up to diameter beyond which further expansion is inhibited.

39. A method of manufacturing a stent graft comprising:

positioning a cover comprising a composite material under tension sufficient to overcome the retraction force of said composite material on at least one surface of a stent at an expanded diameter of said stent to form a stent graft; and

bonding said cover to said stent,

wherein said composite material comprises at least one expanded fluoropolymer membrane and an elastomer, and

wherein said expanded fluoropolymer membrane comprises serpentine fibrils.

40. The method of claim 39, wherein each said serpentine fibril has a width of about 1.0 micron or less.

41. The method of claim 40, wherein each said serpentine fibril has a width of about 0.5 micron or less.

42. The method of claim 39, wherein said cover is wrinkle-free before loading and after deployment.

43. The method of claim 39, wherein said cover is positioned on at least one of an outer surface and an inner surface of said stent.

44. The method of claim 39, wherein said at least one expanded fluoropolymer membrane comprises a plurality of pores and said elastomer is present in substantially all of said pores.

45. The method of claim 39, further comprising applying an adhesive to said stent prior to positioning said cover on said at least one surface of said stent.

46. The method of claim 39, wherein the expanded fluoropolymer membrane comprises a microstructure of substantially only serpentine fibrils,

47. The method of claim 39, wherein the fluoropolymer membrane comprises polytetrafluoroethylene.

48. The method of claim 39, wherein the fluoropolymer membrane comprises a microstructure of substantially only fibrils.

49. The method of claim 39, wherein when said cover is wrinkle-free when expanded to about 80% of a nominal diameter.

50. The method of claim 39, wherein said cover has a diameter substantially larger than said nominal diameter.

51. The method of claim 39, wherein said bonding step occurs substantially at room temperature.

52. The method of claim 39, wherein said cover in a relaxed state has a diameter substantially smaller than said expanded diameter of said stent.

53. The method of claim 39, wherein the fluoropolymer membrane comprises a plurality of serpentine fibrils.

54. A stent graft comprising:

a stent having a wall with at least one opening, an outer surface, and an inner surface; and

a cover affixed to said stent at a size greater than said stent diameter, said cover comprising a composite material comprising at least one expanded fluoropolymer membrane and an elastomer,

wherein said cover is free of wrinkles when radially expanded to about 80% of said stent diameter.

55. The stent graft of claim 54, wherein said cover is affixed to said outer surface.

56. The stent graft of claim 54, wherein said cover is affixed to said inner surface.

57. The stent graft of claim 54, wherein said cover is affixed to said outer surface and said inner surface.

58. The stent graft of claim 54, wherein said elastomer is present in pores of said fluoropolymer membrane.

59. The stent graft of claim 54, wherein the fluoropolymer membrane comprises a microstructure of substantially only fibrils.

60. The stent graft of claim 54, wherein the fluoropolymer membrane comprises a plurality of serpentine fibrils.

61. The stent graft of claim 54, wherein each said serpentine fibril has a width of about 1.0 micron or less.

62. The stent graft of claim 61, wherein each said serpentine fibril has a width of about 0.5 micron or less.

63. The stent graft of claim 54, wherein the expanded fluoropolymer membrane comprises a microstructure of substantially only serpentine fibrils.

64. The stent graft of claim 54, wherein said composite material can be radially expanded up to a diameter beyond which further expansion is inhibited.

65. A stent graft comprising:

a stent having a wall with at least one opening, an outer surface, and an inner surface; and

a cover comprising at least one expanded fluoropolymer membrane and an elastomer, said cover being provided on at least one of said outer surface and said inner surface and covering at least a portion of the at least one opening,

wherein said expanded fluoropolymer membrane comprises serpentine fibrils.

66. The stent graft of claim 65, wherein each said serpentine fibril has a width of about 1.0 micron or less.

67. The stent graft of claim 66, wherein each said serpentine fibril has a width of about 0.5 micron or less.

68. The stent graft of claim 65, wherein said cover is wrinkle-free when radially expanded to about 80% of a nominal diameter.

69. The stent graft of claim 65, wherein said elastomer is present in pores of said fluoropolymer membrane.

70. The stent graft of claim 65, wherein said expanded fluoropolymer membrane comprises a plurality of pores and said elastomer is present in substantially all of said pores.

71. The stent graft of claim 65, wherein the fluoropolymer comprises polytetrafluoroethylene.

72. The stent graft of claim 65, wherein the fluoropolymer membrane comprises a plurality of serpentine fibrils.

73. The stent graft of claim 65, wherein the fluoropolymer membrane comprises a microstructure of substantially only fibrils.

74. The stent graft of claim 65, wherein said fluoropolymer membrane is circumferentially wrapped around said stent.

75. The stent graft of claim 65, wherein said fluoropolymer membrane is axially wrapped around said stent.

76. The stent graft of claim 65, wherein said fluoropolymer membrane is helically wrapped around said stent.

77. The stent graft of claim 65, wherein said fluoropolymer membrane is both circumferentially and axially wrapped around said stent.

78. The stent graft of claim 65, wherein the stent comprises a self-expanding stent.

79. The stent graft of claim 65, wherein the cover is provided on the inner surface of the stent.

80. The stent graft of claim 65, wherein the cover is provided on the outer surface of the stent.

81. The stent graft of claim 65, wherein the covering is provided on the outer and inner surfaces of the stent.

82. The stent graft of claim 65, wherein elastic properties are present in the axial direction of the stent graft.

83. The stent graft of claim 65, wherein elastic properties are present in the radial direction of the stent graft.

84. The stent graft of claim 65, wherein said cover can be radially expanded up to a diameter beyond which further expansion is inhibited.

85. The stent graft of claim 65, wherein the expanded fluoropolymer membrane comprises a microstructure of substantially only serpentine fibrils.

86. The stent graft of claim 65, wherein said elastomer is selected from the group consisting of perfluoromethylvinyl ether-tetrafluoroethylene copolymers, perfluoro(alkyl vinyl ether)-tetrafluoroethylene copolymers, silicones and polyurethanes.

87. A method of manufacturing a tubular member comprising:

positioning an expanded fluoropolymer membrane having therein an elastomer under tension sufficient to overcome the retraction force of said fluoropolymer membrane onto a mandrel;

bonding said fluoropolymer membrane to itself to form a tubular member; and

removing said tubular membrane from said mandrel,

wherein said expanded fluoropolymer membrane comprises serpentine fibrils.

88. The stent graft of claim 87, wherein each said serpentine fibril has a width of about 1.0 micron or less.

89. The stent graft of claim 88, wherein each said serpentine fibril has a width of about 0.5 micron or less.